Mjørkadalur is a valley on the Faroese island of Streymoy in the Tórshavnar municipality.

Criminals from the Faroe Islands who serve longer sentences are sent to prisons in Denmark, as the detention centre only has room for 12 inmates.

[1] It was the site of a Danish military installation (Island Command Faroes) and NATO early warning radar system until the Danish authorities closed it, and handed the key of the building to the Mayor of Tórshavn on 2 July 2002.

[4][5] One of the radars is still operating but it is only watching civilian aircraft traffic in the area.

[6] The location is at the head of a valley where the clouds can be seen forming to travel over nearby peaks.